Copper Alloy C72900
UNS C72900
C72900 (Toughmet 3) is the highest-strength Cu-Ni-Sn spinodal alloy, approximately Cu-15Ni-8Sn, supplied as bar, tube and plate in TB00, TF00, mill-hardened TM tempers and TX00.
Reference datasheet — C72900 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the TF00 condition
C72900 tempers and conditions
C72900 is supplied in 7 conditions, soft to hard. TF00 is the default FabDigit quotes; the values on this page are for it.
Compare all 7 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution heat treated | Soft solution-annealed stock for deep forming/machining of complex parts before customer spinodal ageing. | 280 | 520 | 35 | 78 HRB | 4.5 % IACS |
Mill hardened, half hard | Choose when stamped/formed springs and contacts must still bend appreciably after mill hardening. | 655 | 760 | 9 | 25 HRC | 7 % IACS |
Mill hardened, full hard | Balanced mill-hardened temper for connector springs needing higher stress relaxation resistance with moderate bending. | 760 | 860 | 7 | 29 HRC | 7.2 % IACS |
Mill hardened, extra hard | High-strength mill-hardened strip for flat springs and clips with mostly straight or gentle-radius forming. | 895 | 965 | 5 | 33 HRC | 7.5 % IACS |
TF00Default Solution heat treated and precipitation hardened | Standard high-strength bearing/bushing condition — pick for machined bushings, wear plates and downhole hardware. | 1,000 | 1,105 | 10 | 35 HRC | 7.5 % IACS |
Mill hardened, spring hard | Maximum-strength mill-hardened strip for highly loaded springs where forming is limited to shallow bends. | 1,000 | 1,070 | 4 | 36 HRC | 7.5 % IACS |
cold worked after ageing, extra-high strength rod | Cold-worked-and-aged rod for the highest yield strength, e.g. fasteners, valve stems and heavily loaded pins. | 1,105 | 1,200 | 6 | 39 HRC | 7 % IACS |
What is C72900?
C72900 (Toughmet 3) is the highest-strength Cu-Ni-Sn spinodal alloy, approximately Cu-15Ni-8Sn, supplied as bar, tube and plate in TB00, TF00, mill-hardened TM tempers and TX00. It delivers steel-like strength with 1000 MPa yield, 1105 MPa tensile, 10% elongation, 330 HB (35 HRC) and a 131 GPa modulus, together with good corrosion and wear resistance, which makes it a non-beryllium bearing and spring alloy. Conductivity is 7.5% IACS, thermal conductivity 35 W/m·K and maximum service temperature 250 °C. Machinability is good for the family (65) but formability is very low (20) and fusion welding is not recommended; C72800 is the lower-strength, more formable option. C72900 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,050°C (1,922 °F). C72900 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 99% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 131 GPa (19 Msi).
What is C72900 used for?
- bearings & bushings
- gears
- high-load springs
- downhole oilfield components
Advantages
- High strength — 1,000 MPa (145 ksi), better than 99% of copper alloy grades
- Good corrosion resistance — 78/100, better than 94% of copper alloy grades
- Stiff — 131 GPa (19 Msi), better than 91% of copper alloy grades
- Easy to machine — 65/100, better than 76% of copper alloy grades
Limitations
- High embodied carbon — 7 kg CO₂/kg, worse than 96% of copper alloy grades
- Poor heat conductor — 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades
- Low electrical conductivity — 7.5 % IACS, worse than 84% of copper alloy grades
- Difficult to weld — 25/100, worse than 78% of copper alloy grades
- Limited ductility — 10%, worse than 76% of copper alloy grades
C72900 properties
Typical room-temperature values for C72900-TF00; bars are the position among copper alloy grades.
Physical3
C72900 has a density of 8.86 g/cm³ (0.32 lb/in³), heavier than 68% of copper alloy grades. It melts at 1,050°C (1,922 °F).
Mechanical14
C72900 has a yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 99% of copper alloy grades. Elongation at break is 10% and the elastic modulus is 131 GPa (19 Msi).
Thermal5
C72900 is rated for continuous service to 250°C (482 °F). It conducts heat at 35 W/m·K (20.2 BTU/hr·ft·°F), worse than 88% of copper alloy grades. Thermal expansion is 16.7 µm/m·K (9.28 µin/in·°F).
Electrical3
C72900 conducts electricity at 7.5 % IACS, worse than 84% of copper alloy grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 94% of copper alloy grades.
Sustainability4
Producing a kilogram of C72900 takes about 95 MJ of energy and emits 7 kg of CO₂ — more than 95% of copper alloy grades. Typical recycled content is 25%.
Manufacturability7
C72900's machinability is good (65/100, better than 76% of copper alloy grades); weldability poor (25/100); formability poor (20/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the copper alloy family
Yield strength against density for every copper alloy grade FabDigit runs. C72900 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with C72900
Is C72900 easy to machine?
Machines well in the aged condition with short chips — use sharp carbide, 60–120 m/min, positive rake, rigid setups and flood coolant; avoid dwelling to prevent work hardening.
Can C72900 be welded?
Fusion welding is not recommended (tin segregation and loss of spinodal temper); use mechanical joints, EB/laser only with qualified procedures, or silver brazing accepting local softening.
Can C72900 be formed, bent or molded?
Form in the solution-annealed (TB00) condition or use low mill-hardened tempers (TM02/TM04); aged material is limited to shallow bends with generous radii, then age 350–400 °C to develop strength.
C72900 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Ni | 14.5 – 15.5 | 15 |
| Sn | 7.5 – 8.5 | 8 |
| Mndeoxidiser/grain control | ≤ 0.3 | 0.15 |
| Feimpurity limit | ≤ 0.5 | |
| Znimpurity limit | ≤ 0.5 | |
| Pbimpurity limit | ≤ 0.02 | |
| Curemainder, ~76–78 % | balance |
What surface finishes work on C72900?
Takes a fine polish; no anodising — protect or enhance with passivation, tin/silver/nickel plating, or DLC/PVD for extreme wear; nitric-based pickles remove aged oxide.
Surface treatments FabDigit runs on copper alloy parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Equivalent designations
Standards and trade names that resolve to Copper Alloy C72900 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- Toughmet 3
How much does C72900 cost?
C72900 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
C72900 — frequently asked
What is C72900 used for?
C72900 is typically used for bearings & bushings, gears, high-load springs and downhole oilfield components. In short: strongest Cu-Ni-Sn alloy; beryllium-free bearing alloy; galling-resistant under high load.
What is the yield strength of C72900?
C72900 has a typical yield strength of 1,000 MPa (145 ksi) and a tensile strength of 1,105 MPa (160 ksi) — stronger than 99% of copper alloy grades. Strength varies by condition: see the 7 listed tempers.
Is C72900 easy to machine?
Reasonably — machinability is rated good (65/100, better than 76% of copper alloy grades). Machines well in the aged condition with short chips — use sharp carbide, 60–120 m/min, positive rake, rigid setups and flood coolant; avoid dwelling to prevent work hardening.
Can C72900 be welded?
Not readily — weldability is rated poor (25/100). Fusion welding is not recommended (tin segregation and loss of spinodal temper); use mechanical joints, EB/laser only with qualified procedures, or silver brazing accepting local softening.
What surface finishes work on C72900?
Takes a fine polish; no anodising — protect or enhance with passivation, tin/silver/nickel plating, or DLC/PVD for extreme wear; nitric-based pickles remove aged oxide.
Can C72900 be formed, bent or molded?
Form in the solution-annealed (TB00) condition or use low mill-hardened tempers (TM02/TM04); aged material is limited to shallow bends with generous radii, then age 350–400 °C to develop strength.
What is the maximum service temperature of C72900?
C72900 is rated for continuous use to about 250°C (482 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between C72900-TF00 and C72900-TB00?
TF00 is the default condition — standard high-strength bearing/bushing condition — pick for machined bushings, wear plates and downhole hardware. TB00: soft solution-annealed stock for deep forming/machining of complex parts before customer spinodal ageing. Yield strength is 1,000 MPa in TF00 versus 280 MPa in TB00.
How much does C72900 cost?
C72900 is a high-cost copper alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ToughMet 3 AT / TS Alloy Data (C72900) — Materion Brush Performance Alloys (2023)
- ASTM B929 — Copper-Nickel-Tin Spinodal Alloy Rod, Bar and Shapes — ASTM International (2020)
- ASTM B740 — Copper-Nickel-Tin Spinodal Alloy Strip — ASTM International (2020)
- CDA Alloy Database — C72900 properties — Copper Development Association (2024)
- ASM Handbook Vol. 2 — Properties of Copper and Copper Alloys — ASM International (1990)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.